Overfills

[Ironplates]

What are overfills?
What causes them,
How can they be prevented?

I typically experience them with Oil, Gold, the Yen during high activity price action time periods.

[NinjaTrader_Bertrand]

Ironplates, here's some background on the topic :

An overfill is categorized as when an order returns a "Filled" or "PartFilled" state after the order was already marked for cancellation. The cancel request could have been induced by an explicit CancelOrder() call, from more implicit cancellations like those that occur when another order sharing the same OCO ID is filled, or from things like order expirations.

Generally overfills is a serious issue that can occur when using complex entry conditions that bracket the market in both directions end up with both entries being filled instead of one being cancelled. Overfills can also occur when you place a trade quickly hoping to close a position while a prior order to close the same position already had an in-flight execution.

The exact scenarios in which an overfill can occur is highly dependent on the specific strategy programming. By default, NinjaTrader will protect against overfills by halting the strategy, but there are options in our Unmanaged approach available should you decide to custom program your own overfill handling it is up to you to either prevent overfills from being a possibility in your code or by introducing logic to address overfills should one occur.